Cosmic Scale
RW Cephei
Red hypergiant · About 11,000 light-years
How big is RW Cephei?
RW Cephei is about 1.5 × 10⁹ km across.
See RW Cephei in 3D, at true scale
RW Cephei is a red hypergiant, one of the largest stars known. In 2022 it faded to half its usual brightness when it threw off a cloud of dust, much like Betelgeuse's Great Dimming.
At a glance
| Diameter | 1.5 × 10⁹ km |
|---|---|
| Diameter compared with Earth | 120,000 × Earth |
| Distance | About 11,000 light-years |
| Radius | Around 1,100 Suns |
| Great dimming | 2022 |
| Type | Red hypergiant |
Good to know
- Placed where the Sun is, it would reach almost to the orbit of Jupiter.
- Images from the CHARA array showed its surface patchy with dust during the dimming.
- It is visible in small telescopes in the constellation Cepheus.
- Next smaller: Mu Cephei · 1.4 × 10⁹ km
- Next larger: Westerlund 1-26 · 1.7 × 10⁹ km